The inevitable has happened. After weeks of steadily plummeting polls numbers and increasing political pressure, Herman Cain’s campaign has finally collapsed under the weight of multiple allegations of sexual infidelity. The general assumption is that Newt Gingrich will be the primary benefactor of Cain’s demise. Unlike the former Godfather’s Pizza CEO, Gingrich’s political star has been on the rise. Having pulled virtually even with Mitt Romney in key primary states like Iowa and New Hampshire, Gingrich’s 11th hour surge has further muddied the already murky waters of the GOP presidential pool. Yet many conservatives are wondering: How is it that mere rumors of sexual misconduct can destroy one man’s campaign, while a confirmed serial adulterer can rise to popular prominence notwithstanding the troubling character issues that dog his past?

In other words, why does Newt Gingrich get a free pass and Herman Cain get the boot?

A recent article on Slate.com offers a pretty good explanation, particularly with regard to evangelical Christians’ willingness to overlook – or at least forgive – Gingrich’s less than admirable personal life:

“The leadership of the evangelical right, as loose as it is, has the most influence over a Republican nomination in Iowa, in the caucuses. With a month to go, the candidate who said the right things and built the right-sized lead over Romney is Gingrich. Evangelical kingmakers, whom Newt has courted for years, are discussing how to forgive him.

What does that mean for Gingrich? [Christian radio personality Steve] Deace quoted the Prophet Isaiah for advice. From Isaiah 1:18: ‘Come now, and let us reason together, says the LORD: though your sins be as scarlet, they shall be as white as snow; though they be red like crimson, they shall be as wool.’ That’s doubling as advice for Iowa evangelicals. Reason together. You like Newt anyway. In the scheme of things, his misdeeds aren’t so bad.”

Gingrich – shrewd student of the American psyche that he is – knows that Americans love stories of repentance and redemption. Everyone can identify with this experience, after all. No one is perfect, we’ve all made mistakes and fallen short of the mark. The American people are extraordinarily willing to forgive if they believe the object of their forgiveness is genuinely remorseful and has acknowledged his or her wrongdoing. What they can’t stand, however, is duplicity – someone who lies or equivocates about whether they have done anything wrong in the first place, someone who – for example – feigns confusion over the meaning of the word “is,” or splits hairs over whether engaging in extramarital sexual activity qualifies as “having sex.” We all remember the Monica Lewinsky scandal and the effect it had on Bill Clinton’s presidency. When Clinton finally fessed up to the facts, however, the capacity of the electorate to forgive was remarkable. To this day he remains one of the most popular presidents in modern history.

Herman Cain’s situation became politically untenable because in politics perception becomes reality, and the perception is that Cain must be guilty of something in the face so many accusations coming from so many quarters. This is not a problem that is fixable during a campaign. He had no choice but to voluntarily withdraw, thus preserving a modicum of dignity in the whole unfortunate affair, or flame out in embarrassment and failure. If he is not guilty as charged, he should sue the pants off of his accusers for defamation, subpoena them to testify under oath, put them through the crucible of cross examination, and get the true facts out on the table. Unfortunately, such remedies do not exist in the court of public opinion, where thanks to the media the modus operandi is “verdict first, trial later.”

Meanwhile, Newt gets absolution… at least for the time being. Yet he may successfully dodge the infidelity bullet only to fall victim to over-weening pride. The American public doesn’t respond well to hubris, and this is a trait Mr. Gingrich possesses in spades. Humility has never been Newt’s strong suit. His ego is as big as his outsized intellect. Given enough time and enough soundbytes, his sense of his own grandiosity could derail his candidacy.

Thus, less than a month from the first presidential primary, the field remains uncertain… and somewhat less than inspiring. Mitt Romney wonders why no one likes him, Cain is out, Bachmann, Santorum, Paul and Huntsman don’t’ appear to be gaining traction and have little time for resurgence, and Gingrich is likely incapable of avoiding some form of self-immolation.

So, is it too late for someone else to emerge from the wings? Is it possible that the GOP’s candidate is still sitting on the sidelines, waiting for the chaff to blow away, planning his or her entry? Jeb Bush and Mike Huckabee are two names that come to mind. One thing is certain: This is a very fluid situation. If the last year has taught Republicans anything, it’s that we should expect the unexpected.